Touch position determining apparatus and method thereof

ABSTRACT

A touch position determining apparatus and method thereof are provided. The touch position determining apparatus is adapted to a sphere. The touch position determining apparatus includes a pressure sensing array and a processing unit. The pressure sensing array is coupled below the sphere and includes a plurality of pressure sensing nodes. The pressure sensing array generates a pressure deformation area in response to a touch operation performed on a surface of the sphere, and generates a pressure signal set by the pressure sensing nodes corresponding to the pressure deformation area. The processing unit is connected to the pressure sensing array and determines a touch position of the touch operation performed on the surface of the sphere according to the pressure signal set.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 102121185, filed on Jun. 14, 2013. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

TECHNICAL FIELD

The disclosure relates to a determining apparatus and a method thereof. Particularly, the disclosure relates to a touch position determining apparatus and a method thereof.

BACKGROUND

Most of crystal ball products in the market are used for static display and decoration. A part of the crystal ball products has simple dynamic functions, for example, a crystal ball embedded with a music box or embedded with a doll having simple mechanical movements, etc., such as a baby cradle crystal ball, a ballet girl crystal ball music box and a mouse helicopter music box, etc. In such kind of crystal balls that have simple dynamic functions, the doll movement and music play rely on a combination of clockworks and gears, and mechanical driving. Such kind of dynamic is preset fixed movements and music, which is lack of ability to interact with the user.

Another type of crystal ball that has an interactive function may have sensors, an actuator and a large base, for example, a 3D magic crystal ball and an i-ball, etc. Such type of crystal ball that has the interactive function is configured with pressure sensors or lens sensors, etc. for detecting user's behavior. A signal processing device and image identification software are configured in the large base for detecting the user's behavior (for example, a touch operation etc.). Therefore, a corresponding operation is executed according to the user's behavior, such that the user may have an operation experience of interacting with the crystal ball. However, a few of the crystal ball products in the market have such interactive function.

A sensor generally detects a touch position of the user performed on a surface of the crystal ball through a non-contact manner such as infrared or ultrasound, etc. However, since the crystal ball is generally filled up with water, etc., when the touch position is detected through the mechanism of infrared or ultrasound, etc., the touch position probably could not be accurately determined due to a blind angle in detection.

SUMMARY

The disclosure is directed to a touch position determining apparatus and a method thereof, which is adapted to determine a touch position of a touch operation performed on a surface of a sphere.

The disclosure provides a touch position determining apparatus adapted to a sphere. The touch position determining apparatus includes a pressure sensing array and a processing unit. The pressure sensing array is coupled below the sphere and includes a plurality of pressure sensing nodes. The pressure sensing array forms a pressure deformation area in response to a touch operation performed on a surface of the sphere, and generates a pressure signal set by the pressure sensing nodes corresponding to the pressure deformation area. The processing unit is coupled to the pressure sensing array and determines a touch position of the touch operation performed on the surface of the sphere according to the pressure signal set.

Another exemplary embodiment of the disclosure provides a method for determining a touch position, which is adapted to a sphere. A pressure sensing array is coupled below the sphere, and the pressure sensing array includes a plurality of pressure sensing nodes. The method includes following steps. When a touch operation is performed on a surface of the sphere, the pressure sensing array forms a pressure deformation area in response to the touch operation, and generates a pressure signal set by the pressure sensing nodes corresponding to the pressure deformation area. A touch position of the touch operation performed on the surface of the sphere is determined according to the pressure signal set.

According to the above descriptions, the disclosure provides the touch position determining apparatus and the method thereof, by which when the touch operation is performed on the surface of the sphere, the touch position of the touch operation on the surface of the sphere is determined according to the pressure signal set generated by the pressure sensing nodes corresponding to the pressure deformation area on the pressure sensing array.

In order to make the aforementioned and other features and advantages of the disclosure comprehensible, several exemplary embodiments accompanied with figures are described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.

FIG. 1 illustrates a touch position determining apparatus according to an embodiment of the disclosure.

FIG. 2 is a flowchart illustrating a method for determining a touch position according to an embodiment of the disclosure.

FIG. 3 is a top view of the touch position determining apparatus of FIG. 1.

FIG. 4A is a top view of a sphere illustrated according to the embodiment of FIG. 3.

FIG. 4B is a side view of the sphere illustrated according to the embodiment of FIG. 3.

FIG. 5A is a schematic diagram of correcting a pressure center point when an included angle between a force exerting direction of a touch operation and a force exerting direction perpendicular to a surface of a sphere is increased to the left according to an embodiment of the disclosure.

FIG. 5B is a schematic diagram of correcting a pressure center point when an included angle between a force exerting direction of a touch operation and a force exerting direction perpendicular to a surface of a sphere is increased to the right according to an embodiment of the disclosure.

FIG. 5C is a schematic diagram of correcting a pressure center point when a force exerting direction of a touch operation is perpendicular to a tangent surface at a touch position according to an embodiment of the disclosure.

FIG. 6A is a schematic diagram of correcting a pressure center point when an included angle between a force exerting direction of a touch operation and a force exerting direction perpendicular to a surface of a sphere is increased downwards according to an embodiment of the disclosure.

FIG. 6B is a schematic diagram of correcting a pressure center point when an included angle between a force exerting direction of a touch operation and a force exerting direction perpendicular to a surface of a sphere is increased upwards according to an embodiment of the disclosure.

FIG. 6C is a schematic diagram of correcting a pressure center point when a force exerting direction of a touch operation is perpendicular to a tangent surface at a touch position according to an embodiment of the disclosure.

FIG. 7 is a top view of a touch position determining apparatus according to an embodiment of the disclosure.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

FIG. 1 illustrates a touch position determining apparatus according to an embodiment of the disclosure. In the present embodiment, the touch position determining apparatus 100 includes a pressure sensing array 120 and a processing unit 130. The touch position determining apparatus 100 is adapted to a sphere 110. The sphere 110 can be a spherical or near spherical object of any material, for example, a crystal ball, a plastic ball, a glass ball or similar. Moreover, the content in the sphere 110 can be any substance, for example, water, a doll and a model, etc. The pressure sensing array 120 is coupled below the sphere 110, and has a plurality of pressure sensing nodes 125. The pressure sensing nodes 125 may generate a pressure signal set PSS in response to a touch operation peformed on the sphere 110. The pressure signal set PSS may include a plurality of pressure sensing signals, and the pressure sensing signals are, for example, the voltage variation signals generated by the pressure sensing nodes 125 when the pressure sensing nodes 125 detect a pressure from the sphere 110.

In an embodiment, after the pressure sensing nodes 125 generate voltage variation signals, a signal reading unit (not shown) can be used to transform the voltage variation signals from analog signals into digital signals, so as to constitute the pressure signal set PSS. The signal reading unit may include signal buffer(s), signal amplifier(s), a plurality of channel switches and an analog-to-digital converter (ADC). The signal buffer(s) may be used for executing impedance matching and receiving the voltage variation signals. The signal amplifier(s) may be coupled to the signal buffer(s), and may be used for amplifying the voltage variation signals. The channel switches are respectively coupled to the signal amplifier(s), and are used for switching a plurality of transmission paths used for transmitting the amplified voltage variation signals. The ADC is coupled to the channel switches, and is used for performing analog-to-digital conversions on the amplified voltage variation signals.

In other embodiments, the pressure sensing array 120 can also be implemented by a piezoelectric thin film or a piezoresistive thin film. Moreover, the pressure sensing array 120 may have any area, shape and size. The pressure sensing array 120 can be disposed below the sphere 110, and forms a pressure deformation area in response to the touch operation performed on the sphere 110. In detail, when the touch operation is performed on a surface of the sphere 110 (for example, a user presses the sphere 110 with a finger), the sphere 110 correspondingly generates a displacement, and the pressure sensing array 120 disposed below the sphere 110 receives a pressure corresponding to the touch operation. Now, the thin film on the pressure sensing array 120 is depressed in response to the pressure of the touch operation, and forms the aforementioned pressure deformation area. While the pressure deformation area is formed, the pressure sensing nodes 125 corresponding to the pressure deformation area generate the pressure sensing signals in response to the pressure of the touch operation, so as to constitute the pressure signal set PSS.

Generally, a thickness of the piezoelectric thin film (or the piezoresistive thin film) is relatively thin, and the designer can dispose a flexible material with a fixed thickness under the piezoelectric thin film (or the piezoresistive thin film) to increase a degree of depression of the pressure sensing array 120 generated in response to the pressure of the touch operation. If the flexible material has a certain fixed thickness, when the pressure of the touch operation is increased to a certain degree, the degree of depression of the pressure sensing array 120 is probably not increased due to that the depression reaches a bottom of the flexible material and the piezoelectric thin film (or the piezoresistive thin film). In other words, the size of the pressure deformation area is not enlarged along with increase of the pressure. Therefore, when the pressure sensing array 120 is designed, the designer can select the flexible material with a suitable thickness according to a pressure (for example, a user's pressing strength) probably exerted on the piezoelectric thin film (or the piezoresistive thin film), such that the pressure deformation area may maintain a fixed radius (which can be defined as a radius of the pressure deformation area) under the touch operation.

The processing unit 130 is coupled to the pressure sensing array 120, and determines a touch position of the touch operation performed on the sphere 110 according to the pressure signal set PSS. The processing unit 130 is, for example, a micro controller unit (MCU), a central processor or other programmable microprocessor.

FIG. 2 is a flowchart illustrating a method for determining a touch position according to an embodiment of the disclosure. FIG. 3 is a top view of the touch position determining apparatus of FIG. 1. The method provided by the embodiment of FIG. 2 is adapted to the touch position determining apparatus 100 of FIG. 3. Referring to FIG. 2 and FIG. 3, detailed steps of the method of FIG. 2 are described below with reference of various parameters of FIG. 3

In the present embodiment, it is assumed that the user touches the sphere 110 at a certain touch position. Therefore, in step S202, when a touch operation is performed on the sphere 110, the pressure sensing array 120 forms is a pressure deformation area 310 in response to the touch operation, and the pressure sensing nodes 125 (which are indicated by circles in the pressure deformation area 310) corresponding to the pressure deformation area 310 generate the pressure signal set PSS. For simplicity's sake, the sphere 110 corresponds to a coordinate system, and the coordinate system may include an origin 312, an X-axis, a Y-axis and a Z-axis.

Then, in step S204, the processing unit 130 calculates a pressure deformation area center point (which is represented by coordinates (X₂, Y₂)) of the pressure deformation area 310 on a X-Y plane and a first azimuth angle φ_(A) of the pressure deformation area center point (X₂, Y₂) relative to the X-axis on the X-Y plane according to the pressure signal set PSS, where X₂ is a coordinate of the pressure deformation area center point on the X-axis, Y₂ is a coordinate of the pressure deformation area center point on the Y-axis, and the X-Y plane is defined by the X-axis and the Y-axis.

In detail, after the pressure signal set PSS is obtained, the processing unit 130 accordingly learns the pressure sensing nodes 125 (i.e. the circles in the pressure deformation area 310) corresponding to the pressure deformation area 310. Moreover, the processing unit 130 calculates a coverage range of the pressure deformation area 310 according to positions of the pressure sensing nodes 125, so as to obtain a maximum value (which is represented by X₃) and a minimum value (which is represented by X₁) of the pressure deformation area 310 on the X-axis, and a maximum value (which is represented by Y₁) and a minimum value (which is represented by Y₃) of the pressure deformation area 310 on the Y-axis. Therefore, the processing unit 130 takes an average value of the maximum value and the minimum value of the X-coordinate of the boundary of the pressure deformation area 310 to serve as an X-coordinate of the pressure deformation area center point (i.e. X₂=(X₁+X₃)/2). Moreover, the processing unit 130 takes an average value of the maximum value and the minimum value of the Y-coordinate of the boundary of the pressure deformation area 310 to serve as a Y-coordinate of the pressure deformation area center point (i.e. Y₂=(Y₁+Y₃)/2). After obtaining the pressure deformation area center point (X₂, Y₂), the processing unit 130 can calculate an included angle (i.e. the first azimuth angle φ_(A)) between the pressure deformation area center point (X₂, Y₂) and the X-axis according to a trigonometric formula. Therefore, when the X-coordinate of the pressure deformation area center point (X₂, Y₂) is greater than 0 (i.e. X₂>0), the first azimuth angle φ_(A) is tan⁻¹ (Y₂/X₂), and when the X-coordinate of the pressure deformation area center point (X₂, Y₂) is not greater than 0 (i.e. X₂≦0), the first azimuth angle φ_(A) is 180+ tan⁻¹(Y₂/X₂).

In step S206, the processing unit 130 calculates a first maximum distance between the X-coordinate of the pressure deformation area center point and the X-coordinate of the boundary of the pressure deformation area, and a second maximum distance between the Y-coordinate of the pressure deformation area center point and the Y-coordinate of the boundary of the pressure deformation area, and sets a maximum value of the first maximum distance and the second maximum distance as a specific distance DI. In other words, the processing unit 130 calculates a distance between X₂ of the pressure deformation area center point (X₂, Y₂) and X₁ or a distance between X₂ and X₃ (i.e. the calculated distance between X₂ and X₁ or the calculated distance between X₂ and X₃ can be the first maximum distance), and calculates a distance between Y₂ and Y₁ or a distance between Y₂ and Y₃ (i.e. the calculated distance between Y₂ and Y₁ or the calculated distance between Y₂ and Y₃ can be the second maximum distance), and then the processing unit 130 obtains the maximum value of the first maximum distance and the second maximum distance to serve as the specific distance DI. In the embodiment of FIG. 3, the processing unit 130 respectively calculates the distance between X₂ and X₁ the distance between X₂ and X₃, the distance between Y₂ and Y₁ and the distance between Y₂ and Y₃, and obtains the maximum value of the calculated distances to serve as the specific distance DI.

Then, in step S208, the processing unit 130 determines whether a pressure deformation area radius R₂ of the pressure deformation area 310 is substantially greater than or equal to the specific distance DI. According to the aforementioned description, the pressure deformation area 310 can maintain the fixed pressure deformation area radius R₂ in case that the touch operation is performed. According to the pressure deformation area 310 illustrated in FIG. 3, the specific distance DI is substantially equal to the pressure deformation area radius R₂. In other embodiments, since the aforementioned various coordinate parameters and the calculated values may have a little error due to a configuration density of the pressure sensing nodes 125 in the pressure sensing array 120, when the determination operation of the step S208 is executed, the processing unit 130 can perform the determination operation according to an error range set by the designer. Namely, when a difference between the specific distance DI and the pressure deformation area radius R₂ is smaller than the error range, the processing unit 130 takes the specific distance DI and the pressure deformation area radius R₂ to be substantially equivalent, though the disclosure is not limited thereto. Therefore, in case that the specific distance DI and the pressure deformation area radius R₂ are substantially equivalent, a step S212 is executed after the step S208. However, in other embodiments, when the specific distance DI and the pressure deformation area radius R₂ are substantially not equivalent, a step S210 executed, which is described later in another embodiment.

In the step S212, the processing unit 130 can set an X-coordinate and a Y-coordinate of a pressure center point according to the pressure deformation area center point (X₂, Y₂). The aforementioned pressure center point is, for example, a main pressure point generated by the sphere 110 in the pressure deformation area 310 in response to the touch operation. In step S214, the processing unit 130 calculates a Z-coordinate (which is represented by Z_(A)) of the pressure center point according to the X-coordinate (which is represented by X_(A)) and the Y-coordinate (which is represented by Y_(A)) of the pressure center point and a sphere radius of the sphere 110. In the present embodiment, since the pressure deformation area center point has been set as the pressure center point in the step S212, the X-coordinate (X_(A)) and the Y-coordinate (Y_(A)) of the pressure center point are respectively X₂ and Y₂. Therefore, the Z-coordinate (Z_(A)) of the pressure center point can be obtained according to an equation. For example, the Z-coordinate (Z_(A)) of the pressure center point can be (r²−X_(A) ²-−Y_(A) ²)^(1/2), where the sphere radius r is the radius of the sphere 110.

In step S216, the processing unit 130 calculates a second azimuth angle (which is represented by θ_(A)) of the pressure center point relative to the Z-axis according to the X-coordinate (X_(A)), the Y-coordinate (Y_(A)) and the Z-coordinate (Z_(A)) of the pressure center point, where the second azimuth angle (θ_(A)) is, for example, obtained according to an equation tan⁻¹((X_(A) ²+Y_(A) ²)^(1/2)/Z_(A)).

In order to clearly indicate the relationship of the aforementioned various parameters in the sphere 110, FIG. 4A and FIG. 4B are provided below. FIG. 4A is a top view of the sphere illustrated according to the embodiment of FIG. 3. Referring to FIG. 4A, when the touch operation is performed, the processing unit 130 can calculate the X-coordinate (X_(A)), the Y-coordinate (Y_(A)) and the Z-coordinate (Z_(A)) of the pressure center point according to the aforementioned instructions/teachings. Therefore, the pressure center point can be represented as (X_(A), Y_(A), Z_(A)) in the coordinate system. Moreover, since an included angle of a connection line between the center of the sphere 110 and the pressure center point in the X-Y plane of projection coordinate (i.e. X-Y coordinate) and the X-axis is equivalent to the first azimuth angle φ_(A), the included angle can be indicated in a manner as that shown in FIG. 4A.

FIG. 4B is a side view of the sphere illustrated according to the embodiment of FIG. 3. Referring to FIG. 4B, after the coordinates of the pressure center point in the coordinate system are obtained, the processing unit 130 calculates the second azimuth angle θ_(A) of the pressure center point relative to the Z-axis according to the aforementioned instructions/teachings. The second azimuth angle θ_(A) can be indicated in a manner as that shown in FIG. 4B.

Those with ordinary skill in the art should understand that in case that the sphere radius (r), the coordinates of the pressure center point, the first azimuth angle φ_(A), and the second azimuth angle θ_(A) are already known, the X-coordinate (X_(A)), the Y-coordinate (Y_(A)) and the Z-coordinate (Z_(A)) of the pressure center point can be represented by a following mathematical equation:

X _(A) =r·sin θ_(A) cos φ_(A)

Y _(A) =r·sin θ_(A) sin φ_(A)

Z _(A) =r·cos θ_(A)

It should be noticed that when a force exerting direction of the touch operation is perpendicular to a tangent plane of the sphere 110, the processing unit 130 can directly set a position on the surface of the sphere 110 that is symmetric to the pressure center point relative to the origin 312 as a touch position of the touch operation. However, when the force exerting direction of the touch operation is not perpendicular to the tangent plane of the sphere 110, according to the calculated pressure center point, the processing unit 130 probably cannot obtain the correct touch position directly through the aforementioned method due to shift of the force exerting direction. Therefore, the processing unit 130 performs a step S218 shown in FIG. 2 after obtaining the pressure center point.

Referring to FIG. 2, in step S218, the processing unit 130 can correct the pressure center point according to a reference force exerting direction, the first azimuth angle φ_(A), and the second azimuth angle θ_(A). The aforementioned reference force exerting direction is parallel to the force exerting direction of the touch operation, and passes through the origin 312, and can be measured by a G-sensor 140 or a similar device that is coupled to the sphere 110 and the processing unit 130. In order to describe the step S218 in detail, FIGS. 5A-5C and FIGS. 6A-6C are provided below for descriptions.

FIG. 5A is a schematic diagram of correcting a pressure center point when an included angle between the force exerting direction of the touch operation and a force exerting direction perpendicular to the surface of the sphere is increased to the left according to an embodiment of the disclosure. In the present embodiment, it is assumed that the touch operation is taken place at a position P according to a force exerting direction B. Now, based on the pressure deformation area (not shown) generated on the pressure sensing array 120, the processing unit 130 calculates a pressure center point E according to the aforementioned steps S202-S214. However, if the processing unit 130 directly sets a position P′ symmetric to the pressure center point E relative to the origin 312 as the touch position of the touch operation, a wrong touch position determination result is obtained (since the position P′ is different to the touch position P). A reason thereof is that when the touch operation is taken place at the position P′ according to a reference direction A (which is perpendicular to tangent plane at the position P′), a pressure deformation area substantially equivalent to the pressure deformation area corresponding to the pressure center point E is generated. Therefore, in order to find the correct touch position P, the processing unit 130 can correct the pressure center point E to a pressure center point F, so as to obtain the correct touch position P. The pressure center point F can be correspondingly calculated by the processing unit 130 when the touch operation is taken place at the touch position P according to a reference direction D which is perpendicular to tangent plane at the touch position P.

In order to obtain a first correction angle φ used for correcting the pressure center point E to the pressure center point F, a plurality of parameters are defined in FIG. 5A to facilitate understanding of the conception of the embodiment. First, a reference force exerting direction B′ is parallel to the force exerting direction B and passes through the origin 312. An included angle φ₁ is included between the reference direction D and the reference force exerting direction B′. An included angle φ₂ is included between the reference direction A and the reference force exerting direction B′. An included angle φ_(A)′ is included between the reference direction A and the X-axis. A first included angle φ_(B)′ is included between the reference force exerting direction B′ and the X-axis, which can be obtained by the G-sensor 140 according to x-component and y-component of the reference force exerting direction B′. According to FIG. 5A, it is known that the first correction angle φ is equal to a sum of the included angle φ₁ and the included angle φ₂ (i.e. φ=φ₁+φ₂). Moreover, the included angle φ₁ is equal to an included angle φ₁′ (which are alternate interior angles). Moreover, since the pressure center point E, the origin 312 and the touch position P construct an isosceles triangle, it is known that the included angle φ₁′ is equal to an included angle φ₂′. Moreover, the included angle φ₂ is equal to the included angle φ₂′ (which are corresponding angles). In other words, φ₁=φ₁′=φ₂=φ₂′, where the included angle φ₂ can be obtained by subtracting the included angle φ_(A)′ from the first included angle φ_(B)′ (i.e. φ₂=φ_(B)′−φ_(A)′), and the included angle φ_(A)′ can be obtained according to the first azimuth angle φ_(A) corresponding to the pressure center point E (which is, φ_(A)′=φ_(A)−180, in this example). Therefore, the processing unit 130 can calculate the first correction angle φ according to the first included angle φ_(B)′ and the first azimuth angle φ_(A). The first correction angle φ can be represented by a following equation:

φ=φ₁+φ₂=2×φ₂=2×(φ_(B)′−φ_(A)′)

Then, the processing unit 130 adds the first azimuth angle φ_(A) by the first correction angle φ to correspondingly correct the first azimuth angle, so as to correct the pressure center point E to the pressure center point F.

In brief, when the force exerting direction B of the touch operation is shifted to the left, the processing unit 130 can correct the pressure center point E rightwards to the pressure center point F according to the first correction angle φ. It should be noticed that when the force exerting direction of the touch operation is shifted to the right, the processing unit 130 can also perform the similar operation to correct the pressure center point.

FIG. 5B is a schematic diagram of correcting a pressure center point when an included angle between the force exerting direction of the touch operation and a force exerting direction perpendicular to the surface of the sphere is increased to the right according to an embodiment of the disclosure. In the present embodiment, definitions of the parameters may refer to related description of the embodiment of FIG. 5A, which are not repeated. According to a deduction process similar as that described in the embodiment of FIG. 5A, those skilled in the art can deduce a following equation:

φ=φ₁+φ₂=2×φ₂=2×(φ_(B)′−φ_(A)′).

Then, the processing unit 130 adds the first azimuth angle φ_(A) by the first correction angle φ to correct the pressure center point E to the pressure center point F. It should be noticed that since the first included angle φ_(B)′ is smaller than the included angle φ_(A)′, when the processing unit 130 adds the first azimuth angle φ_(A) by the first correction angle φ, the processing unit 130 substantially performs an operation of φ_(A)−|φ|. In brief, when the force exerting direction B of the touch operation is shifted to the right, the processing unit 130 can still correct the pressure center point E leftwards to the pressure center point F according to the first correction angle φ.

According to another conception, regardless of whether the force exerting direction of the touch operation is shifted to the left or to the right, the first correction angle can be calculated according to a same mathematical equation, so as to correspondingly correct the pressure center point. In order to further verify the result, and embodiment of FIG. 5C is provided for description.

FIG. 5C is a schematic diagram of correcting a pressure center point when the force exerting direction of the touch operation is perpendicular to the tangent surface at the touch position according to an embodiment of the disclosure. In the present embodiment, definitions of the parameters may refer to related description of the embodiment of FIG. 5A, which are not repeated. According to FIG. 5C, it is known that the first included angle φ_(B)′ is equal to the included angle φ_(A)′. Therefore, the processing unit 130 correspondingly calculates the first correction angle φ to be 0 (i.e., φ=2×(φ_(B)′−φ_(A)′)=0). In other words, the pressure center point E is equal to the pressure center point F.

According to the instructions in the embodiment of FIG. 5A to FIG. 5C, the processing unit 130 can horizontally correct the pressure center point when the force exerting direction of the touch operation is horizontally shifted (i.e. shifted to the left or to the right). Then, embodiments of FIGS. 6A-6C are provided to describe another correction method performed on the pressure center point by the processing unit 130 when the force exerting direction of the touch operation is vertically shifted (i.e. shifted upwards or downwards).

FIG. 6A is a schematic diagram of correcting a pressure center point when an included angle between the force exerting direction of the touch operation and a force exerting direction perpendicular to the surface of the sphere is increased downwards according to an embodiment of the disclosure. In the present embodiment, definitions of the parameters are the same to that of the embodiment of FIG. 5A, which are not repeated. Moreover, an included angle θ₁ is included between the reference direction D and the reference force exerting direction B′. An included angle θ₂ is included between the reference direction A and the reference force exerting direction B′. An included angle θ_(A)′ is included between the reference direction A and the X-Y plane. A second included angle θ_(B)′ is included between the reference force exerting direction B′ and the X-Y plane, which can be obtained by the G-sensor 140 according to x-component, y-component and z-component of the reference force exerting direction B′. According to FIG. 6A, it is known that the second correction angle θ is equal to a sum of the included angle θ₁ and the included angle θ₂ (i.e. θ=θ₁+θ₂). Moreover, the included angle θ₁ is equal to an included angle θ₁′ (which are alternate interior angles). Moreover, since the pressure center point E, the origin 312 and the touch position P construct an isosceles triangle, it is known that the included angle θ₁′ is equal to an included angle θ₂′. Moreover, the included angle θ₂ is equal to the included angle θ₂′ (which are corresponding angles). In other words, θ₁=θ₁′=θ₂=θ₂′, where the included angle θ₂ can be obtained by subtracting the included angle θ_(A)′ from the second included angle θ_(B)′ (i.e. θ₂=θ_(B)′−θ_(A)′), and the included angle θ_(A)′ can be obtained according to the second azimuth angle θ_(A) corresponding to the pressure center point E (which is, θ_(A)′=θ_(A)−90, in this example). Therefore, the processing unit 130 can calculate the second correction angle θ according to the second included angle θ_(B)′ and the second azimuth angle θ_(A). The second correction angle θ can be represented by a following equation:

θ=θ₁+θ₂=2×θ₂=2×(θ_(B)′−θ_(A)′).

Then, the processing unit 130 adds the second azimuth angle θ_(A) by the second correction angle θ to correspondingly correct the second azimuth angle, so as to correct the pressure center point E to the pressure center point F.

In brief, when the force exerting direction B of the touch operation is shifted downwards, the processing unit 130 can correct the pressure center point E downwards to the pressure center point F according to the second correction angle θ. It should be noticed that when the force exerting direction of the touch operation is shifted upwards, the processing unit 130 can also perform the similar operation to correct the pressure center point.

FIG. 6B is a schematic diagram of correcting a pressure center point when an included angle between the force exerting direction of the touch operation and a force exerting direction perpendicular to the surface of the sphere is increased upwards according to an embodiment of the disclosure. In the present embodiment, definitions of the parameters may refer to related description of the embodiment of FIG. 6A, which are not repeated. According to a deduction process similar as that described in the embodiment of FIG. 6A, those skilled in the art can deduce a following equation:

θ=θ₁+θ₂=2×θ₂−2×(θ_(B)′−θ_(A)′)

Then, the processing unit 130 adds the second azimuth angle θ_(A) by the second correction angle θ to correct the pressure center point E to the pressure center point F. It should be noticed that since the second included angle θ_(B)′ is smaller than the included angle θ_(A)′, when the processing unit 130 adds the second azimuth angle θ_(A) by the second correction angle θ, the processing unit 130 substantially performs an operation of θ_(A)−|θ|. In brief, when the force exerting direction B of the touch operation is shifted upwards, the processing unit 130 can still correct the pressure center point E upwards to the pressure center point F according to the second correction angle θ.

According to another conception, regardless of whether the force exerting direction of the touch operation is shifted upwards or downwards, the second correction angle can be calculated according to a same mathematical equation, so as to correspondingly correct the pressure center point. In order to further verify the result, and embodiment of FIG. 6C is provided for description.

FIG. 6C is a schematic diagram of correcting a pressure center point when the force exerting direction of the touch operation is perpendicular to the tangent surface at the touch position according to an embodiment of the disclosure. In the present embodiment, definitions of the parameters may refer to related description of the embodiment of FIG. 6A, which are not repeated. According to FIG. 6C, it is known that the second included angle θ_(B)′ is equal to the included angle θ_(A)′. Therefore, the processing unit 130 correspondingly calculates the second correction angle θ to be 0 (i.e., θ=2×(θ_(B)′−θ_(A)′)=0). In other words, the pressure center point E is equal to the pressure center point F.

According to instructions of FIGs. 5A-5C and FIGS. 6A-6C, the processing unit 130 can correct the pressure center point according to the corrected first azimuth angle and second azimuth angle. The X-coordinate (which is represented by X_(A)′), the Y-coordinate (which is represented by Y_(A)′) and the Z-coordinate (which is represented by Z_(A)′) of the pressure center point can be represented as follows:

X _(A) ′=r·sin(θ_(A)+θ)cos(φ_(A)+φ)

Y _(A) ′=r·sin(θ_(A)+θ)sin(φ_(A)+φ)

Z _(A) ′=r·cos(θ_(A)+θ)

Referring to FIG. 2, after the pressure center point is corrected according to instructions of FIGS. 5A-5C and FIGS. 6A-6C (step S218), in step S220, the processing unit 130 can set a position on the surface of the sphere 110 that is symmetric to the corrected pressure center point relative to the origin 312 as the touch position of the touch operation. In an embodiment, the X-coordinate (which is represented by X_(D)), the Y-coordinate (which is represented by Y_(D)), and the Z-coordinate (which is represented by Z_(D)) of the touch position P can be calculated according to the instructions of FIGS. 5A-5C and/or FIGS. 6A-6C:

X _(D) =r·sin(180°−(θ_(A)+θ))cos(φ_(A)+φ−180°)

Y _(D) =r·sin(180°−(θ_(A)+θ))sin(φ_(A)+φ−180°)

Z _(D) =r·cos(180°−(θ_(A)+θ))

In brief, according to the touch position determining apparatus and the method thereof provided by the disclosure, when the touch operation is performed on the sphere, the touch position of the touch operation on the surface of the sphere is found according to the corresponding pressure deformation area on the pressure sensing array. Moreover, when the force exerting direction of the touch operation is shifted, the touch position determining apparatus can correspondingly correct the pressure center point, so as to obtain the correct touch position. In this way, regardless of the material of the sphere, the touch position can be obtained through the apparatus and the method provided by the disclosure. Similarly, regardless of the content in the sphere, the touch position can be obtained through the apparatus and the method provided by the disclosure.

FIG. 7 is a top view of a touch position determining apparatus according to an embodiment of the disclosure. In the present embodiment, it is assumed that the touch operation correspondingly forms a pressure deformation area 710 on the pressure sensing array 120. Now, since a force exerting mode of the sphere 110 is different to that of the embodiment of FIG. 3, although determination of the touch position can also be performed according to the method of FIG. 2, details thereof are slightly different to the embodiment of FIG. 3, which are described in detail below.

Referring to FIG. 2 and FIG. 7, first, the touch position determining apparatus 100 executes the steps S202-S206, and details of the steps can refer to related descriptions of the embodiment of FIG. 2, which are not repeated. After the steps S202-S206 are executed, the pressure deformation area center point (which is represented by (X₂, Y₂)), the first azimuth angle φ_(A) of the pressure deformation area center point (X₂, Y₂) relative to the X-axis on the X-Y plane, and the specific distance DI are obtained. In FIG. 7, related setting of the specific distance DI can refer to the description of the embodiment of FIG. 3, which is not repeated.

Then, in the step S208, the processing unit 130 determines whether the pressure deformation area radius R₂ of the pressure deformation area 710 is substantially greater than or equal to the specific distance DI. As that shown in FIG. 7, the pressure deformation area radius R₂ is greater than the specific distance DI. Therefore, after the step S208, the step S210 is executed, and in the step S210, the processing unit 130 can set the X-coordinate (X_(A)) and the Y-coordinate (Y_(A)) of the pressure center point 730 according to the first azimuth angle φ_(A), the pressure deformation area radius R₂, and a specific pressure sensing node 720 closest to the original 312 in the pressure deformation area 710. The specific pressure sensing node 720 can be found according to the pressure sensing nodes and the origin 312 when the pressure sensing nodes in the pressure deformation area 710 are known. In the present embodiment, the X-coordinate (which is represented by X_(C)) and the Y-coordinate (which is represented by Y_(C)) of the specific pressure sensing node 720 can be used to deduce the X-coordinate (X_(A)) and the Y-coordinate (Y_(A)) of the pressure center point 730. In detail, according to FIG. 7, it is known that the X-coordinate (X_(A)) of the pressure center point 730 can be represented by (R₂× cos φ_(A))+X_(C), and the Y-coordinate (Y_(A)) of the pressure center point 730 can be represented by (R₂× sin φ_(A))+Y_(C).

After the X-coordinate (X_(A)) and the Y-coordinate (Y_(A)) of the pressure center point 730 are obtained, the processing unit 130 continually executes the steps S214-S220 to find the touch position of the touch operation. Details of the steps S214-S220 may refer to aforementioned related descriptions, which are not repeated.

In an embodiment, since a maximum value of the specific distance DI is not greater than the pressure deformation area radius R₂, in the step S208, it is determined whether the pressure deformation area radius R₂ is substantially equal to the specific distance DI. When the pressure deformation area radius R₂ of the pressure deformation area 710 is substantially not equal to the specific distance DI, it represents that the specific distance DI is not greater than the pressure deformation area radius R₂. Therefore, the step S210 is executed, and details thereof can refer to related descriptions of the aforementioned embodiment, which are not repeated.

In summary, the disclosure provides the touch position determining apparatus and the method thereof, by which when the touch operation is performed on the surface of the sphere, the touch position of the touch operation on the surface of the sphere is found according to the corresponding pressure deformation area on the pressure sensing array. Moreover, when the force exerting direction of the touch operation is shifted, the touch position determining apparatus can correspondingly correct the pressure center point to obtain the correct touch position.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents. 

What is claimed is:
 1. A touch position determining apparatus, adapted to a sphere, the touch position determining apparatus comprising: a pressure sensing array, coupled below the sphere and comprising a plurality of pressure sensing nodes, wherein the pressure sensing array forms a pressure deformation area in response to a touch operation performed on a surface of the sphere, and generates a pressure signal set by the pressure sensing nodes corresponding to the pressure deformation area; and a processing unit, coupled to the pressure sensing array, and determining a touch position of the touch operation performed on the surface of the sphere according to the pressure signal set.
 2. The touch position determining apparatus as claimed in claim 1, wherein the sphere corresponds to a coordinate system, wherein the coordinate system has an origin, an X-axis, a Y-axis and a Z-axis, and the processing unit is configured to: calculate a pressure deformation area center point of the pressure deformation area on a X-Y plane and a first azimuth angle of the pressure deformation area center point relative to the X-axis on the X-Y plane according to the pressure signal set, wherein the X-Y plane is defined by the X-axis and the Y-axis; set an X-coordinate and a Y-coordinate of a pressure center point according to the pressure deformation area center point, wherein the pressure center point is a main pressure point generated by the sphere in the pressure deformation area in response to the touch operation; calculate a Z-coordinate of the pressure center point according to the X-coordinate and the Y-coordinate of the pressure center point and a sphere radius of the sphere; calculate a second azimuth angle of the pressure center point relative to the Z-axis according to the X-coordinate, the Y-coordinate and the Z-coordinate of the pressure center point; correct the pressure center point according to a reference force exerting direction, the first azimuth angle, and the second azimuth angle, wherein the reference force exerting direction is parallel to a force exerting direction of the touch operation, and passes through the origin; and set a position on the surface of the sphere that is symmetric to the corrected pressure center point relative to the origin as the touch position of the touch operation.
 3. The touch position determining apparatus as claimed in claim 2, wherein the processing unit is configured to: calculate a first maximum distance between the X-coordinate of the pressure deformation area center point and X-coordinate of a boundary of the pressure deformation area, and a second maximum distance between the Y-coordinate of the pressure deformation area center point and Y-coordinate of the boundary of the pressure deformation area, and set a maximum value of the first maximum distance and the second maximum distance as a specific distance; and determine whether a pressure deformation area radius of the pressure deformation area is substantially equal to the specific distance, and if yes, set the X-coordinate and the Y-coordinate of the pressure center point according to the pressure deformation area center point.
 4. The touch position determining apparatus as claimed in claim 2, wherein the processing unit takes an average value of a maximum value and a minimum value of the X-coordinate of a boundary of the pressure deformation area to serve as the X-coordinate of the pressure deformation area center point; the processing unit takes an average value of a maximum value and a minimum value of the Y-coordinate of a boundary of the pressure deformation area to serve as a Y-coordinate of the pressure deformation area center point; and when the X-coordinate of the pressure deformation area center point is greater than 0, φ_(A) is tan⁻¹(Y₂/X₂), and when the X-coordinate of the pressure deformation area center point is not greater than 0, φ_(A) is 180+ tan⁻¹(Y₂/X₂), wherein φ_(A) is the first azimuth angle, wherein X₂ is the X-coordinate of the pressure deformation area center point, and Y₂ is the Y-coordinate of the pressure deformation area center point.
 5. The touch position determining apparatus as claimed in claim 3, wherein when the pressure deformation area radius of the pressure deformation area is substantially not equal to the specific distance, the processing unit sets the X-coordinate and the Y-coordinate of the pressure center point according to the first azimuth angle, the pressure deformation area radius, and a specific pressure sensing node closest to the original in the pressure deformation area.
 6. The touch position determining apparatus as claimed in claim 5, wherein when the processing unit sets the pressure center point according to the first azimuth angle, the pressure deformation area radius and the specific pressure sensing node, X_(A) is (R₂× cos φ_(A))+X_(C), and Y_(A) is (R₂× sin φ_(A))+Y_(C), wherein X_(A) is the X-coordinate of the pressure center point, and Y_(A) is the Y-coordinate of the pressure center point, wherein R₂ is the pressure deformation area radius, φ_(A) is the first azimuth angle, X_(C) and Y_(C) are respectively the X-coordinate and the Y-coordinate of the specific pressure sensing node.
 7. The touch position determining apparatus as claimed in claim 2, further comprising a G-sensor coupled to the sphere and the processing unit, and calculating a first included angle between the reference force exerting direction and the X-axis; wherein the processing unit calculates a first correction angle according to the first included angle and the first azimuth angle; the G-sensor calculates a second included angle between the reference force exerting direction and the X-Y plane; the processing unit calculates a second correction angle according to the second included angle and the second azimuth angle; the processing unit respectively corrects the first azimuth angle and the second azimuth angle according to the first correction angle and the second correction angle; and the processing unit corrects the pressure center point according to the corrected first azimuth angle and the corrected second azimuth angle.
 8. A method for determining a touch position, adapted to a sphere, wherein a pressure sensing array is coupled below the sphere, and the pressure sensing array comprises a plurality of pressure sensing nodes, the method for determining the touch position comprising: forming a pressure deformation area by the pressure sensing array in response to a touch operation when the touch operation is performed on a surface of the sphere, and generating a pressure signal set by the pressure sensing nodes corresponding to the pressure deformation area; and determining the touch position of the touch operation performed on the surface of the sphere according to the pressure signal set.
 9. The method for determining the touch position as claimed in claim 8, wherein the sphere corresponds to a coordinate system, the coordinate system has an origin, an X-axis, a Y-axis and a Z-axis, and the step of determining the touch position of the touch operation performed on the surface of the sphere according to the pressure signal set comprises: calculating a pressure deformation area center point of the pressure deformation area on a X-Y plane and a first azimuth angle of the pressure deformation area center point relative to the X-axis on the X-Y plane according to the pressure signal set, wherein the X-Y plane is defined by the X-axis and the Y-axis; setting an X-coordinate and a Y-coordinate of a pressure center point according to the pressure deformation area center point, wherein the pressure center point is a main pressure point generated by the sphere in the pressure deformation area in response to the touch operation; calculating a Z-coordinate of the pressure center point according to the X-coordinate and the Y-coordinate of the pressure center point and a sphere radius of the sphere; calculating a second azimuth angle of the pressure center point relative to the Z-axis according to the X-coordinate, the Y-coordinate and the Z-coordinate of the pressure center point; correcting the pressure center point according to a reference force exerting direction, the first azimuth angle, and the second azimuth angle, wherein the reference force exerting direction is parallel to a force exerting direction of the touch operation, and passes through the origin; and setting a position on the surface of the sphere that is symmetric to the corrected pressure center point relative to the origin as the touch position of the touch operation.
 10. The method for determining the touch position as claimed in claim 9, wherein the step of setting the X-coordinate and the Y-coordinate of the pressure center point according to the pressure deformation area center point comprises: calculating a first maximum distance between the X-coordinate of the pressure deformation area center point and X-coordinate of a boundary of the pressure deformation area, and a second maximum distance between the Y-coordinate of the pressure deformation area center point and Y-coordinate of the boundary of the pressure deformation area, and setting a maximum value of the first maximum distance and the second maximum distance as a specific distance; and determining whether a pressure deformation area radius of the pressure deformation area is substantially equal to the specific distance, and if yes, setting the X-coordinate and the Y-coordinate of the pressure center point according to the pressure deformation area center point, wherein the pressure center point is a main pressure point generated by the sphere in the pressure deformation area in response to the touch operation.
 11. The method for determining the touch position as claimed in claim 9, wherein the step of calculating the pressure deformation area center point of the pressure deformation area on the X-Y plane and the first azimuth angle of the pressure deformation area center point relative to the X-axis on the X-Y plane according to the pressure signal set comprises: taking an average value of a maximum value and a minimum value of the X-coordinate of a boundary of the pressure deformation area to serve as the X-coordinate of the pressure deformation area center point; and taking an average value of a maximum value and a minimum value of the Y-coordinate of a boundary of the pressure deformation area to serve as a Y-coordinate of the pressure deformation area center point, wherein when the X-coordinate of the pressure deformation area center point is greater than 0, φ_(A) is tan⁻¹(Y₂/X₂), and when the X-coordinate of the pressure deformation area center point is not greater than 0, φ_(A) is 180+ tan⁻¹(Y₂/X₂), wherein φ_(A) is the first azimuth angle, wherein X₂ is the X-coordinate of the pressure deformation area center point, and Y₂ is the Y-coordinate of the pressure deformation area center point.
 12. The method for determining the touch position as claimed in claim 10, wherein the step of determining whether the pressure deformation area radius of the pressure deformation area is substantially equal to the specific distance, the method further comprises: setting the X-coordinate and the Y-coordinate of the pressure center point according to the first azimuth angle, the pressure deformation area radius, and a specific pressure sensing node closest to the original in the pressure deformation area when the pressure deformation area radius of the pressure deformation area is substantially not equal to the specific distance.
 13. The method for determining the touch position as claimed in claim 12, wherein the step of setting the X-coordinate and the Y-coordinate of the pressure center point according to the first azimuth angle, the pressure deformation area radius, and the specific pressure sensing node closest to the original in the pressure deformation area comprises: when the pressure center point is set according to the first azimuth angle, the pressure deformation area radius and the specific pressure sensing node, X_(A) is (R₂× cos φ_(A))+X_(C), and Y_(A) is (R₂× sin φ_(A))+Y_(C), wherein X_(A) is the X-coordinate of the pressure center point, and Y_(A) is the Y-coordinate of the pressure center point, wherein R₂ is the pressure deformation area radius, φ_(A) is the first azimuth angle, X_(C) and Y_(C) are respectively the X-coordinate and the Y-coordinate of the specific pressure sensing node.
 14. The method for determining the touch position as claimed in claim 9, wherein the step of correcting the pressure center point according to the reference force exerting direction, the first azimuth angle, and the second azimuth angle comprises: calculating a first included angle between the reference force exerting direction and the X-axis through a G-sensor coupled to the sphere; calculating a first correction angle according to the first included angle and the first azimuth angle; calculating a second included angle between the reference force exerting direction and the X-Y plane through the G-sensor; calculating a second correction angle according to the second included angle and the second azimuth angle; respectively correcting the first azimuth angle and the second azimuth angle according to the first correction angle and the second correction angle; and correcting the pressure center point according to the corrected first azimuth angle and the corrected second azimuth angle. 